This is a bit...eeeeeehhhh...like, I feel like it's kind of right, but also kind of wrong...?
I agree that, to have a good story, you do need to try to present smart ideas. If your story is filled with stupid/dull statements and doesn't make logical sense, people will naturally think less of it even if they continue reading. They just won't be able to be immersed in your world if they always have to stop to figure out what the hell you're trying to say.
HOWEVER...vocabulary isn't the only way to present that you are smart. ^^; In fact, it's a very superficial way to try to present intelligence, and one that's liable to make you look a lot less intelligent if you slip up. Constantly using 9-dollar words in slightly inaccurate ways (because you don't fully understand them...) just makes you look like a poser and a clown. =/
I think writing earnestly is a much better way to go about things. Don't waste energy pretending to be an author who sounds "right"; the only "right" kind of author to be is yourself.
If you like to look up fun new words and add them to your vocabulary (carefully and through understanding their normal context and usage) then go ahead. But if you don't, if you're more comfortable talking 'plain', then that's fine too. You can show how smart you are in other ways, like by writing clever characters who solve difficult problems, or by adding interesting insights and observations about the world.
This is just my two cents, but I think this is kind of a mean question...? ^^; I mean, personally I've been giving writing advice for years, and nothing I've written has been published or 'successful' by any stretch of the imagination (and yet, I've never been asked this...probably because it's mean...).
I'll assume you're expecting a 'no' (which I understand tbh) but if OP were to answer 'yes', would it really change how you feel about their advice...? Is it not enough to criticize it on its own merits? Lots of professionals give bad advice every day; getting a book published or even just getting people to look at it isn't necessarily an indication of artistic skill or insight.
I think this is admittedly better advice than Point 8, even if it may not look that way at first glance. Yeah, it does sound better on paper to "write about people without labels", but on the other hand, minorities are called that for a reason. ^^; And the fact that writing about them is seen as a trend (or a genre...) is itself an indicator of the inequality that still exists, and the necessity for people to actually have to seek out representation.
And they won't find you if you don't tell them you're there. ^^; There are ways to do this without being obnoxious; simply tagging your work appropriately and leaving it at that is fine.
....Dropping a story just because your fans aren't engaging with it "correctly" is not exactly a professional attitude. :T
People will ALWAYS see and latch onto whatever they want in your stories, even if it's 'lowest common denominator' stuff like their favorite ship (and the more popular you get as an author, the more it will happen). First of all, there's nothing really wrong with that, I'm sure we've all done it at some point, even if we never said it out loud...secondly, it's a little odd to imply that the lesbian relationship wasn't an important aspect of the story and that your fans were wrong to focus on it, and simultaneously decide the rest of the story wasn't worth telling because they kept commenting on it. In the end, you still allowed shipping to ruin your story.
If their comments were offensive/made you uncomfortable, I could understand wanting to quit...but if it were me, I'd either disable comments, or just drop the whole rest of the story and THEN leave.
I work HARD on my writing, and no amount of horny strangers are going to make me abandon a story that I'm proud of. Besides, if your work is popular enough to attract regular commenters, it's a sure bet that you have silent readers who are also following along and may genuinely appreciate everything that you're trying to do. I think they deserve to see the experience through to the end.